Optical films and other devices have been developed for a variety of applications, including for use as decorative articles and to enhance or alter characteristics of displays. In particular, there are instances when it is desirable to anisotropically reflect or otherwise scatter light. For example, in many display and projection screen applications, a broad horizontal viewing angle is desirable because a user or viewer may be positioned to the side of the display or projection screen. On the other hand, the vertical viewing angle typically does not need to be as broad because the user or viewer is typically positioned with the display or projection screen at or near eye level. Accordingly, it can be desirable to have an anisotropic display with a relatively broad horizontal viewing angle, but a relatively narrow vertical viewing angle.
One method to modify the viewing angle includes the use of surface structure, such as a lenticular lens screen, where one dimensional lens structures are molded onto plastic substrates. Light is focused by the cylindrical-like lens structures onto a diffusive film to achieve asymmetric diffusion. However, lenticular screens contain a series of tangible grooves which can be expressed as a frequency. This frequency can interfere with the pixel frequency in liquid crystal based projection displays and generate Moire fringes. Thus, the use of current lenticular screens is limited for high definition image display in which pixel frequencies are higher.